<template>
	<div class="goods-sku">
		<dl v-for="item in goods.specs" :key="item.id">
			<dt>{{ item.name }}</dt>
			<dd>
				<template v-for="val in item.values" :key="val.name">
					<img
						:class="{ selected: val.selected, disabled: val.disabled }"
						@click="clickSpecs(item, val)"
						v-if="val.picture"
						:src="val.picture"
					/>
					<span :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)" v-else>
						{{ val.name }}
					</span>
				</template>
			</dd>
		</dl>
	</div>
</template>
<script>
	export default {
		name: 'XtxSku',
	}
</script>

<script setup>
	import { watchEffect } from 'vue'
	import getPowerSet from './power-set'

	const props = defineProps({
		// specs:所有的规格信息  skus:所有的sku组合
		goods: {
			type: Object,
			default: () => ({ specs: [], skus: [] }),
		},
	})
	const emit = defineEmits(['change'])

	const spliter = '★'
	let pathMap = {}

	// 初始化禁用状态
	function initDisabledStatus(specs, pathMap) {
		if (specs && specs.length > 0) {
			specs.forEach(spec => {
				spec.values.forEach(val => {
					// 设置禁用状态
					val.disabled = !pathMap[val.name]
				})
			})
		}
	}

	// 得到当前选中规格集合
	const getSelectedArr = specs => {
		const selectedArr = []
		specs.forEach((spec, index) => {
			const selectedVal = spec.values.find(val => val.selected)
			if (selectedVal) {
				selectedArr[index] = selectedVal.name
			} else {
				selectedArr[index] = undefined
			}
		})
		return selectedArr
	}

	// 更新按钮的禁用状态
	const updateDisabledStatus = (specs, pathMap) => {
		// 遍历每一种规格
		specs.forEach((item, i) => {
			// 拿到当前选择的项目
			const selectedArr = getSelectedArr(specs)
			// 遍历每一个按钮
			item.values.forEach(val => {
				if (!val.selected) {
					selectedArr[i] = val.name
					// 去掉undefined之后组合成key
					const key = selectedArr.filter(value => value).join(spliter)
					val.disabled = !pathMap[key]
				}
			})
		})
	}

	// 根据skus数据得到路径字典对象
	const getPathMap = skus => {
		const pathMap = {}
		if (skus && skus.length > 0) {
			skus.forEach(sku => {
				// 1. 过滤出有库存有效的sku
				if (sku.inventory) {
					// 2. 得到sku属性值数组
					const specs = sku.specs.map(spec => spec.valueName)
					// 3. 得到sku属性值数组的子集
					const powerSet = getPowerSet(specs)
					// 4. 设置给路径字典对象
					powerSet.forEach(set => {
						const key = set.join(spliter)
						// 如果没有就先初始化一个空数组
						if (!pathMap[key]) {
							pathMap[key] = []
						}
						pathMap[key].push(sku.id)
					})
				}
			})
		}
		return pathMap
	}

	watchEffect(() => {
		// 得到所有字典集合
		pathMap = getPathMap(props.goods.skus)
		// 组件初始化的时候更新禁用状态
		initDisabledStatus(props.goods.specs, pathMap)
	})

	const clickSpecs = (item, val) => {
		if (val.disabled) return false
		// 选中与取消选中逻辑
		if (val.selected) {
			val.selected = false
		} else {
			item.values.forEach(bv => {
				bv.selected = false
			})
			val.selected = true
		}
		// 点击之后再次更新选中状态
		updateDisabledStatus(props.goods.specs, pathMap)
		// 把选择的sku信息传出去给父组件
		// 触发change事件将sku数据传递出去
		const selectedArr = getSelectedArr(props.goods.specs).filter(value => value)
		// 如果选中得规格数量和传入得规格总数相等则传出完整信息(都选择了)
		// 否则传出空对象
		if (selectedArr.length === props.goods.specs.length) {
			// 从路径字典中得到skuId
			const skuId = pathMap[selectedArr.join(spliter)][0]
			const sku = props.goods.skus.find(sku => sku.id === skuId)
			// 传递数据给父组件
			emit('change', {
				skuId: sku.id,
				price: sku.price,
				oldPrice: sku.oldPrice,
				inventory: sku.inventory,
				specsText: sku.specs.reduce((p, n) => `${p} ${n.name}：${n.valueName}`, '').trim(),
			})
		} else {
			emit('change', {})
		}
	}
</script>

<style scoped lang="scss">
	@mixin sku-state-mixin {
		border: 1px solid #e4e4e4;
		margin-right: 10px;
		cursor: pointer;

		&.selected {
			border-color: $xtxColor;
		}

		&.disabled {
			opacity: 0.6;
			border-style: dashed;
			cursor: not-allowed;
		}
	}

	.goods-sku {
		padding-left: 10px;
		padding-top: 20px;

		dl {
			display: flex;
			padding-bottom: 20px;
			align-items: center;

			dt {
				width: 50px;
				color: #999;
			}

			dd {
				flex: 1;
				color: #666;

				> img {
					width: 50px;
					height: 50px;
					margin-bottom: 4px;
					@include sku-state-mixin;
				}

				> span {
					display: inline-block;
					height: 30px;
					line-height: 28px;
					padding: 0 20px;
					margin-bottom: 4px;
					@include sku-state-mixin;
				}
			}
		}
	}
</style>
